This invention relates to a runway collision avoidance system which monitors a runway to detect obstructions therein and to warn aircraft and the control tower when an obstruction is present on an active runway.
During low-visibility conditions, it is often impossible for either pilots or air traffic-controllers to visually inspect or observe an active runway for the presence of aircraft or ground vehicles. Under such conditions it is generally accepted practice to assume that all taxiing aircraft and ground vehicles are proceeding in compliance with proper ground control or tower control clearances. Due to the complexity of most modern airports, however, the possibility of operational errors is always present and is significantly increased during low-visibility conditions when landmarks and reference points are obscured from vision. When an error or misunderstanding does occur, the results can be catastrophic.
On Mar. 27, 1977, during low-visibility conditions at Tenerife Airport, Canary Islands, the worst disaster in the history of commercial aviation occurred when a KLM B747 collided during takeoff with a Pan American B747 which was taxiing on the runway. Five hundred eighty-one lives were lost. A similar accident occurred at Chicago O-Hare Airport in December, 1972, also with tragic results. These and numerous other accidents and incidents clearly indicate the need for a positive means of runway traffic detection.
The encroachment of wildlife onto a runway also presents a hazard. As recently as Aug. 28, 1982, a U.S. Air DC-9 was seriously damaged during take-off when it struck a deer which had wandered onto the active runway at Pittsburg International Airport.
A more recent need for an automatic runway monitoring and detection system arises from the Federal Aviation Administration's decision to close airport control towers at many of the nation's major airports during the late evening and early morning hours. For example, New York LaGuardia Airport, one of the most congested facilities in the country, and the site of several near collisions in recent years, no longer provides tower control during the hours of 0100 to 0600 local while leaving the airport runways open to both arrivals and departures without restriction to published operating minimums.